Do not abort on zero length reads

eg....



  Read Header Len:  32
  Name Length:      14
  # of Bases:       43
  Clip Qual Left:   15
  Clip Qual Right:  12
  Clip Adap Left:   0
  Clip Adap Right:  0

Flowgram:       1.12    0.00    1.18    0.00    0.12    0.90    0.00    1.03    0.00    0.82    0.00    1.15    0.86    0.00    0.51    0.16    0.60    0.33    1.10    0.00    1.22    0.46    0.49    1.17    0.35    0.00    0.27    0.41
Flow Indexes:   1       3       6       8       10      12      13      15      17      19      21      24      29      31      34      35      37      39      45      47      49      52      53      56      58      58      58      60
Bases:  tcagcgactgtacgactcactatagggagaccgttgtgtctgg
Quality Scores: 29      29      26      25      25      25      15      10      10      10      18      16      17      21      23      17      17      17      28      27      25      28      28      26      26      26      13      20